Television transmission device



Dec. 31, 1940.

HANN S-HEINZ WOLFF TELEVISION TRANSMISSION DEVICE Filed July 16, 1938 2Sheets-Sheet l jnveniur: LWLW 4 Dec. 31, 1940. HANN$.HE|Nz WQLFF2,227,414

TELEVISI ON TRANSMISSION DEVICE Filed July 16, 1938 2 Sheets-Sheet 2Patented Dec. 31, 1940 TELEVISION TRANSMISSION DEVICE Hanns-Heinz Wolfi,Berlin, Germany, assiznor, by mesne assignments, to Loewe Radlo,lnc'., acorporation of New York Application July 16, 1938, Serial No. 219,607 InGermany July 19, 1937 4 Claims.

In television transmissions in which the scanning of the picture takesplace by'means of an iconoscope or the like there result at the receiverdistortions of the picture which, in the case s of picture of highdefinition, may assume unacceptable proportions. These distortions arebased on the chronological delay of the synchronization impulses inrelation to the image signals which result by way of the modulating lostage of the transmitter and the demodulation stage of the receiver.

The Figs. 1-3 are intended to explain the operation of an arrangement ofthis kind. There is: i

i the iconoscope of the transmitter,

tr the synchronizing impulse generator for the line deflection on thetransmitter,

fly the synchronizing impulse generator for the 20 frame deflection,

Zinc the relaxation oscillation generator for the line deflection,

t the relaxation oscillation generator for the frame deflection,

25 t the amplifier of the transmitter,

in Fig. i the iconoscope I possesses a pair of deflecting plates eachiorithe horizontal'and the 40 vertical deflection. The deflectingpotentials are generated in the relaxation oscillation gem craters 3a:and 3y, which are controlled by the impulse generators 2m and 2y. In theamplifier t there are amplified the synchronization im-' pulses of thegenerators 2a: and 231 and the image transmimion; and in the modulator 5following thereon the carrier wave of the transmitter is modulated bythis image potential mixture and passed to the transmitter 6. At thereceiver the so synchronization impulses are filtered out by aseparating device and employed for controlling the relaxation generatorsMa: and My for th deflecting potential of the Braun tube.

The instants of the image signals caused by 55 thescanning in aniconoscope of the transmitter (Clf17M9-5) are dependent on thedeflecting oscillations controlled by the synchronizing impulses. Theinstants of the image signals reproducing the image at the screen or thecathode ray tube of the receiver are dependent on the image signalsgiven 5 from the transmitter. The deflecting oscillations for deflectingthe cathode ray at the receiver is also controlled by the impulse givenfrom the impulse generator or the transmitter. These synchronizingsiwais are longer delayed W on the way between the impulse yenerator oithe transmitter and the deflecting oscillator oi the receiver, than theimage signals on the way bechronizing impulses pass more "elements thanthe image signals, and since the passed elements delay the synchronizingimpulses longer than the image signals. Therefore, at the receiverthepositions of the image signals on the room to duced image are displacedin view of the positions of the image signals on the transmittedpicture. v

The subject matter of the invention is an arrangement for tutating thedistortions oi the to picture at the receiver. This takes place by thetact that the impulses which for controlling the relaxation generatorstr, to for the iconoscope i at the transmitter end experience the samede lay as the pulses ior controilinz the relaxa- W tion generators list,My tor the cathode ray tube it at the receiver...

The arrangement semi-ding to the invention is explained lay Fla. 2. Thesynchronization impulses of the generators to and i are conducted 35only in the known iashion with the image signals to the transmitter forcontrolling the receiver. The connection hetween the impulse generatorstar, ty and the relaxation oscillation v generators to, to as shown inliig. l is omitted. 40 At the aerial coil of the transmitter 5 there isprovided a receiving device l, which receives the televisiontransmissions. The synchronization impulses are filtered out by aseparating device it in the known manner from the mixture ret5 ceivedand employed for controlling the relaxation generators tax, is for theiconoscooe it. The delays in the synchronization impulses hetween theimpulse generator of the transmitter and the relaxation generator of thereceiver acto cordingly exactly correspond to the delays in. theimpulses from the impulse generator to the relaxation generator' for,the iconoscope. In

this way it is accomplished that differences in time between thedeflecting potentials and the 5B image potentials at the cathode raytube of the receiver are eliminated. The arrangement can also beemployed if records are to be made by an iconoscope at a comparativelylarge distance away from the transmitter. In this case the control ofthe relaxation potential generators of the iconoscope also takes placeby the impulse generatorsof the transmitter by way of a specialreceiving device.

Fig. 3 shows a possibility of use of this kind. A televisiontransmission is to be recorded by means of the iconoscope l at acomparatively long distance away from the transmitter, for example on aplaying field. The impulse generators 2a: and 21/ are located at thetelevision transmitter. The synchronization impulses are transmitted inwireless fashion to the portable recording apparatus, where they areemployed for controlling the relaxation oscillation generators 3m, 33located there. In this way it is possible to make the portable recordingapparatus more simple in design and to ensure the synchronization of thereceiver by the transmitter. Th record to be transmitted can be conveyedfrom the recording apparatus to the transmitter by a wire connection orspecial cable. It is also possible, and particularly convenient, toperform the transmission in wireless fashion by the use of an auxiliarytransmitter. In this connection there canbe employed for the auxiliarytransmitter a desired frequency or the same frequency as that ,of themain transmitter or half the frequency or another sub-harmonic frequencyof the main transmitter. If there is employed for the auxiliarytransmitter the same frequency as for the main transmitter, the maintransmitter acts as amplifier. In this case modulating stages anddemodulating stages in the main transmitter can be dispensed with. Whenusing one-half of the frequency or any other sub-harmonic frequency ofthe main transmitter a frequency doubling or multiplication requires tobe performed at the main transmitter. of the method previouslymentionedthe advantage that reactionary effects of the main transmitteron the auxiliary transmitter are avoided. In'Fig. 3 there is shown awire connection for transmitting the contents of the picture to thetransmitter.

I claim:

1. In a television transmitter a cathode ray tube for scanning thepicture, deflecting oscillators for deflecting the cathode ray of saidcathode ray tube in the vertical direction and in the horizontaldirection, generators generating impulses controlling said deflectingoscillators and synchronizing the deflecting oscillators of thereceiver, delaying means consisting of a special device receiving thesynchronizing impulses transmitted by the transmitter and beingcoupledvia a demodulator, arr amplifier amplifying said impulses and aseparating device separating the line and frame synchronizing impulsesfrom the image signals and each from one another to the tube,

This method possesses in face.

deflecting oscillators of said scanning cathode ray-tube.

2. In a television transmitter a cathode ray tube for scanning thepicture, deflecting oscillators for deflecting the cathode ray of saidcathode ray tube in the vertical direction and in the horizontaldirection, generators generating impulses controlling s lid deflectingoscillators and synchronizing the deflecting oscillators of thereceiver, delaying means consisting of a special device receiving thesynchronizing impulses transmitted by the transmitter and being coupledvia a demodulator, an implifler amplifying said impulses and aseparating device separating the line and frame synchronizing impulsesfrom the image signals and each from one another to the deflectingoscillators of said scanning cathode ray said special receiving deviceand said scanning cathode ray tube being placed in a comparatively longdistance from the other parts of the transmitter.

3. In a television transmitter an iconoscope for scanning the picture,deflecting oscillators for deflecting the cathode ray of said cathoderay tube in the vertical direction and in the horizontal direction,generators generating impulses controlling said deflecting oscillatorsand synchronizing the deflecting oscillators oi the receiver, delayingmeans consisting of a special device receiving the synchronizingimpulses transmitted by the transmitter and being coupled via ademodulator, an amplifier amplifying said impulses and a separatingdevice separating the line and frame synchronizing impulses from theimage signals and each from one another to the deflecting oscillators ofsaid scanning cathode ray tube, said special receiving device and saidiconoscope being placed in a comparatively long distance from the otherparts of the transmitter, only the scanning electrode of the iconoscopebeing connected by cable to the modulator of the transmitter.

4. In a television transmitter an iconoscope for scanning the picture,deflecting oscillators for deflecting the cathode ray of said cathoderay tube in the vertical direction and in the horizontal direction,generators generating impulses controlling said deflecting oscillatorsand synchronizing the deflecting oscillators of the receiver, delayingmeans consisting of a special device receiving the synchronizingimpulses transmitted by the transmitter and being coupled via ademodulator, an implifler amplifying said impulses and a separatingdevice separating line and frame synchronizing impulses from the imagesignals and each from one another to the deflecting oscillators of saidscanning cathode ray tube, said special receiving device and saidiconoscope being placed in a comparatively long distance from the otherparts of the transmitter, only the scanning electrode of the iconoscopebeing connected by cable to the modulator of the transmitter, saidspecial receiving and said iconoscope being mounted in a transportabletelevision scanning apparatus.

HANNS-HEINZ WOLFF.

